Field of the Invention
The present invention relates to a thermal energy recovery device that recovers exhaust heat.
Description of the Related Art
Conventionally, there is a known device that recovers thermal energy generated in various facilities. As one example of this device, JP 2012-202374 A describes a power generation device including a circulation flow passage in which an evaporator that evaporates a liquid of a working medium by a heat medium, an expander that expands steam of the working medium, a condenser that condenses the steam of the working medium, and a pump that circulates the working medium are connected in series. In the power generation device described in JP 2012-202374 A, the expander includes a screw rotor, and the screw rotor is rotated by the steam of the working medium expanded in the expander. This screw rotor is connected to a power generator, and the power generator converts rotation of the screw rotor into electric power.
The power generation device described in JP 2012-202374 A further includes a pressure sensor that detects pressure of the working medium on the inlet side of the pump, and a derivation means that detects saturated steam pressure of the working medium from a temperature of the working medium on the inlet side of the pump. The power generation device described in JP 2012-202374 A suppresses generation of cavitation in the pump by adjusting a circulation amount of the working medium in accordance with a pressure difference between the pressure detected in the pressure sensor and the saturated steam pressure derived in the derivation means.
The power generation device described in JP 2012-202374 A suppresses the generation of the cavitation by adjusting the circulation amount of the working medium as described above. However, in a case where the power generation device is mounted on a moving body such as a vessel or a vehicle, there is a possibility that due to vibration of the moving body, the working medium in a gas phase is mixed into a pipe part between the condenser and the pump which should essentially be filled with the working medium in a liquid phase and a gas comes into the pump. As a result, there is a possibility that the cavitation is generated in the pump.